1. Field of the Invention
This invention lies in the field of over-the-road vehicles for transporting and powering an hydraulic seismic vibrator, while operating at high energy efficiency and high time efficiency
2. Description of the Prior Art
In the use of seismic vibrators as seismic sources, the vibrator, while operating rests on a baseplate or pad on the earth, with part of the weight of the truck or vehicle pressing down on the baseplate.
In off-the-road vehicles it has become customary to use articulated vehicles with independent hydraulic drive on each of the 4 wheels. The vibrator is positioned in the middle of the vehicle. However, while the hydrostatic type hydraulic drive gave excellent control of the vehicle and fast starts, the energy efficiency of the hydraulic drive system is low, of the order of 75% or less. This would mean that to get 300 horsepower, an engine of 400 HP. would be required, and means would be required to remove 100 HP. of heat from the hydraulic fluid.
While the hydrostatic hydraulic drive of the off-the-road carriers could be used in an over-the-road vehicle, the poor energy efficiency and cost of such a system makes it impractical.
The improved drive system of this invention, using an hydraulic torque converter, provides better energy efficiency than the hydrostatic hydraulic system, and provides equally high time efficiency in fast starts with engine at full speed.